Enable snmp in VMWare VCSA 5.5

After deploying Oberservium around my home infrastructure, clearly a dull evening. I wondered if it was possible to monitor my vCenter instance, at the end of the day it’s still a linux instance. Logging into the VCSA with ssh and looking around revealed that net-snmp wasn’t installed and obviously this is a requirement for snmp monitoring of a host.

1. Pre-requirements:

  • libsensors4-3.2.0-9.12.1.x86_64.rpm
  • perl-TermReadKey-2.30-277.1.x86_64.rpm

These two rpms need to be downloaded and installed first as a requirement for net-snmp.

2. SLES 11 SP2:

To install net-snmp the correct repository needs adding to YaST2.

  1. ssh into the vcenter instance
  2. start yast2 and select Software -> Software Repositories
  3. Add the following URL: http://download.opensuse.org/repositories/net-snmp:/factory/SLE_11_SP2/ http://ftp.twaren.net/Linux/OpenSuSE/repositories/net-snmp:/factory/SLE_11_SP2/  (thanks Joan)
  4. Go back to the main menu and select Software -> Software Management
  5. Search for net-snmp, select it with the space bar and then choose Accept.

3. Post-install configuration:

/etc/snmp/snmpd.conf

This file will be installed by default, and ideally should be moved/backed up and replaced with a simple version 2c config containing the following:

rocommunity <community name> 
syslocation <location> 
syscontact <contact details>

System startup details:

chkconfing on snmpd
/etc/init.d/snmpd start

4. Firewall / Host access

At this point the snmpd daemon will be running and this can be tested by looking at what ports are listening on VCSA host e.g:

netstat -an | grep 161

However nothing external will be able to connect to this host until the tcpwrappers configuration is modified (this took me about 40 minutes of fiddling to notice (who uses tcpwrappers anymore 😐 )). The following line (WARNING: this allows all hosts access) will need adding to /etc/hosts.allow

snmpd: ALL : ALLOW

5. External testing

From another host preferably on the same network/subnet (avoiding any other firewalls in this instance) test access with snmpwalk e.g:

snmpwalk -v 2c -c <community name> <vcsa host address/IP>

8 thoughts on “Enable snmp in VMWare VCSA 5.5”

  1. Hi Dan

    Thanks for enlightening us!

    Can you perhaps expand on where you got libsensors4-3.2.0-9.12.1.x86_64.rpm and perl-TermReadKey-2.30-277.1.x86_64.rpm from please?

    Thanks
    J

  2. This repo also needs to be added (it contains the remaining dependencies for net-snmp):

    zypper addrepo -f http://download.opensuse.org/distribution/11.2/repo/oss/ opensuse

  3. I got libsensors from opensuse 11.4 distro
    http://ftp5.gwdg.de/pub/opensuse/discontinued/distribution/11.4/repo/oss/suse/x86_64/libsensors4-3.2.0-9.12.1.x86_64.rpm
    I couldn’t find the perl_termReadKey-2.30-277 but found the 2.30-149 ver. But this requires perl be updated to 5.12. Perl 5.10 is installed in 11.2 . So I used the 2.30-138 version.
    I found if you don’t have internet access, you only need the follwong packages in one directory.
    libsensors4-3.2.0-9.12.1.x86_64.rpm, libsnmp30-5.7.3-117.1.x86_64.rpm, net-snmp-5.7.3-117.1.x86_64.rpm, perl-SNMP-5.7.3-117.1.x86_64.rpm, perl-TermReadKey-2.30-138.2.x86_64.rpm,snmp-mibs-5.7.3-117.1.x86_64.rpm
    Then running rpm -i *.rpm inside the directory will install snmpd. Then “chkconfig snmpd on” will make sure it autstarts on reboot. Just don’t forget to alter the config as above.

  4. Hey Dan,

    Just came across this article via the google search term “snmp vcsa 5.5”. Your article was the FIRST result and rightfully so man… flawless walk-through indeed!!

    Huge +1 man!! Thank you VERY MUCH for sharing!

    Regards,

    ://mk

  5. Bummer. The folder: /SLE_11_SP2/ has been removed from the URL you provided.

    Anyone else have an alternative URL?

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